Postzygotic mosaicism of a novel PTPN11 mutation in monozygotic twins discordant for metachondromatosis.

Genetic mosaicism caused by postzygotic mutations is of a great interest due to its role in human disease. Monozygotic twins arising from a single zygote are considered as genetically identical, and any differences likely to be caused by postzygotic events. Thus, phenotypically discordant monozygotic twins offer a unique opportunity to study genotype-phenotype correlation. Here, we present a three-generation family starting from a pair of monozygotic twins discordant for metachondromatosis due to postzygotic p.(Gln175His) variant in the PTPN11 gene. Both phenotypically discordant monozygotic twins harbor p.(Gln175His), however significant differences in mosaic ratio is observed not only between twins, but also within different tissue types within one individual. Phenotypic manifestation of p.(Gln175His) in examined family clearly depends on allele variant fraction (VAF). Individuals harboring constitutional mutation (VAF 50%) present typical metachondromatosis. Milder phenotype is observed in twin harboring high-level mosaicism in the tissue of ectodermal origin (VAF 45%), but not in a blood (VAF 5%). Finally, her twin sister harboring low-level mosaicism in blood (VAF 2%) and nonblood (VAF 12%) tissues is phenotypically normal. Our results provide insights into biological role of mosaicism in disease and further support the usefulness of nonblood tissues as an optimal source of DNA for the identification of postzygotic mutations in phenotypically discordant monozygotic twins.

A recurrent de novo variant supports KCNC2 involvement in the pathogenesis of developmental and epileptic encephalopathy.

Developmental and epileptic encephalopathies (DEE) are a heterogenous group of conditions characterized by the co-occurrence of epilepsy and intellectual/developmental disability. Despite several known DEE-related genes, including these encoding ion channels, still many cases remain without molecular diagnosis. Here, we present a 2-year-old girl with severe DEE in whom whole exome sequencing revealed de novo p.(Val471Leu) variant in the KCNC2 encoding Kv3.2, a voltage-gated potassium channel. To the best of our knowledge, this is the third DEE case due to KCNC2 mutation. Our clinical and molecular findings, particularly the recurrence of p.(Val471Leu) in patient with similar clinical phenotype, further support KCNC2 as a novel DEE-associated gene.

Novel de novo mutation affecting two adjacent aminoacids in the EED gene in a patient with Weaver syndrome.

Overgrowth, macrocephaly, accelerated osseous maturation, variable intellectual disability, and characteristic facial features are the main symptoms of Weaver syndrome, a rare condition caused by mutations in EZH2 gene. Recently, in four patients with Weaver-like symptoms without mutations in EZH2 gene, pathogenic variants in EED were described. We present another patient clinically diagnosed with Weaver syndrome in whom WES revealed an EED de novo mutation affecting two neighboring aminoacids, NM_003797.3:c.917_919delinsCGG/p.(Arg306_Asn307delinsThrAsp) located in one allele (in cis). Our observation, together with previous reports suggests that EED gene testing is warranted in patients with the overgrowth syndrome features and suspicion of Weaver syndrome with normal results of EZH2 gene sequencing.

Application of massively parallel sequencing (MPS) in paternity testing - case report.

Aim of the study: We present the application of massively parallel sequencing (MPS) to extend the scope of analysis in a disputed paternity case. Material and methods: A standard paternity test comprising 16 autosomal STRs was performed by capillary electrophoresis (CE) using 3130xl Genetic Analyzer. Additionally, MPS was performed with ForenSeq DNA Signature Prep Kit and Illumina MiSeq FGx™ Forensic Genomics System. Paternity index (PI) was calculated using DNAStat v.2.1 software. Results>: CE revealed two mismatches, at D21S11 and VWA, between the putative father and the child. Based on MPS results, the mismatches were analyzed and a nonconsensus sequence of allele 14 at the VWA locus in the mother - child pair was identified. Different sequence variants were also detected in 16-16 homozygote alleles at the D3S1358 locus in the child. Conclusions: MPS helped to formulate a definite conclusion regarding the paternity of the defendant and provided full information on intra-allelic polymorphism.

Further evidence for GRIN2B mutation as the cause of severe epileptic encephalopathy.

Epileptic encephalopathies (EE) include a range of severe epilepsies in which intractable seizures or severe sub-clinical epileptiform activity are accompanied by impairment of motor and cognitive functions. Mutations in several genes including ion channels and other genes whose function is not completely understood have been associated to some EE. In this report, we provide a detailed clinical description of a sporadic male patient with early-onset epilepsy and epileptic encephalopathy in whom we performed complete exome sequencing (WES) and identified a GRIN2B mutation. The GRIN2B splicing mutation in intron 10 (c.2011-1G>A) was revealed in a WES study. The result was confirmed by Sanger sequencing. No mutation was found in both parents. Our finding confirms that early-onset EE may be caused not only by gain-of-function variants but also by splice site mutations-in particular those affecting the splice acceptor site of the 10th intron of the GRIN2B gene. © 2016 Wiley Periodicals, Inc.

KIR2DS5 in the presence of HLA-C C2 protects against endometriosis.

Endometriosis is defined as the presence of functional endometrial tissue outside the uterine cavity. Several hypotheses have attempted to explain the etiology and pathogenesis of endometriosis. Recently, it has been suggested that a defect of the natural killer (NK) activity in the recognition and lysis of endometrial cells is one of the crucial points in the development of this disease. Natural killer cells can express killer immunoglobulin-like receptors (KIR), which recognize class I human leukocyte antigens on target cells. We asked whether polymorphisms in KIR, HLA-C, and HLA-B genes are risk factors for endometriosis. We tested 153 women with endometriosis diagnosed on the basis of laparoscopic and histological examination, and 213 control healthy women, who gave birth to at least one child. The frequency of KIR genes in patients was similar to that in controls except for KIR2DS5, which exerted a protective effect only in HLA-C C2-positive individuals. Moreover, KIR2DS5-positive women with endometriosis had 13 times lower chance that the disease would occupy the peritoneum than KIR2DS5- and KIR2DS4del-negative ones (OR = 0.077, P = 0.0061). Similarly, KIR2DS4del-positive endometriotic persons had 11 times lower chance for peritoneal disease (OR = 0.094, P < 0.001). Negative linkage disequilibrium between KIR2DS5 and KIR2DS4del indicates that these genes are mutually exclusive. Our data suggest that KIR2DS5 may be associated with protection from endometriosis, whereas KIR2DS4del seems to be associated with higher disease stages, possibly by exclusion of protective KIR2DS5.

Analysis of four genes involved in the neurodevelopment shows association of rs4307059 polymorphism in the cadherin 9/10 region with completed suicide.

BACKGROUND: We hypothesized that DNA variants affecting neurodevelopment such as rs4307059 (CDH10/CDH9), rs930752 (NRXN1), rs6265 (BDNF) or rs10868235 (NTRK2) may predispose to completed suicide. METHODOLOGY: We used a case-control two-stage approach based on a discovery cohort (557 cases and ∼550 controls) and replication cohort (159 cases and 186 controls). The suicides were ascertained as consecutive cases autopsied at the Department of Forensic Medicine, Medical University of Warsaw, Poland. RESULTS: In the discovery cohort we found an association between suicide and the CC genotype in the rs4307059 polymorphism (OR 1.64, p = 0.012). The trend for an overrepresentation of the CC homozygotes among suicides was replicated in the second cohort (OR 1.97, p = 0.056). Analysis in the pooled cohorts showed that rs4307059 CC was associated with completed suicide (OR 1.71, p = 0.002) also after Bonferroni correction (p(cor.) = 0.024). In an exploratory search for genotype-phenotype correlation we found that males with the rs4307059 CC genotype committed suicide earlier than those with CT/TT genotypes (p = 0.049). CONCLUSIONS: The CC genotype of rs4307059 located in the region between CDH9 and CDH10 is associated with completed suicide in a Polish cohort.

Clinical Presentation of Left Ventricular Noncompaction Cardiomyopathy and Bradycardia in Three Families Carrying HCN4 Pathogenic Variants.

BACKGROUND: Left ventricular noncompaction (LVNC) is a genetically and phenotypically heterogeneous cardiomyopathy in which myocardium consists of two, distinct compacted and noncompacted layers, and prominent ventricular trabeculations and deep intertrabecular recesses are present. LVNC is associated with an increased risk of heart failure, atrial and ventricular arrhythmias and thromboembolic events. Familial forms of primary sinus bradycardia have been attributed to alterations in HCN4. There are very few reports about the association between HCN4 and LVNC. The aim of our study was to characterize the clinical phenotype of families with LVNC and sinus bradycardia caused by pathogenic variants of the HCN4 gene. METHODS: From March 2008 to July 2021, we enrolled six patients from four families with diagnosed isolated LVNC based on the clinical presentation, family history and echocardiographic and cardiovascular magnetic resonance (CMR) evidence of LVNC. Next generation sequencing (NGS) analysis was undertaken for the evaluation of the molecular basis of the disease in each family. RESULTS: A total of six children (median age 11 years) were recruited and followed prospectively for the median of 12 years. All six patients were diagnosed with LVNC by echocardiography, and five participants additionally by CMR. The presence of late gadolinium enhancement (LGE) was found in three children. Sinus bradycardia and dilation of the ascending aorta occurred in five studied patients. In four patients from three families, the molecular studies demonstrated the presence of rare heterozygous HCN4 variants. CONCLUSION: (1) The HCN4 molecular variants influence the presence of a complex LVNC phenotype, sinus bradycardia and dilation of the ascending aorta. (2) The HCN4 alteration may be associated with the early presentation of clinical symptoms and the severe course of the disease. (3) It is particularly important to assess myocardial fibrosis not only within the ventricles, but also in the atria in patients with LVNC and sinus bradycardia.

Prenatal Versus Postnatal Diagnosis of Meckel-Gruber and Joubert Syndrome in Patients with TMEM67 Mutations.

Renal cystic diseases are characterized by genetic and phenotypic heterogeneity. Congenital renal cysts can be classified as developmental disorders and are commonly diagnosed prenatally using ultrasonography and magnetic resonance imaging. Progress in molecular diagnostics and availability of exome sequencing procedures allows diagnosis of single-gene disorders in the prenatal period. Two patients with a prenatal diagnosis of polycystic kidney disease are presented in this article. TMEM67 mutations were identified in both fetuses using a whole-exome sequencing (WES) study. In one of them, the phenotypic syndrome diagnosed prenatally was different from that diagnosed in the postnatal period.

Variable degree of mosaicism for tetrasomy 18p in phenotypically discordant monozygotic twins-Diagnostic implications.

BACKGROUND: Phenotypically discordant monozygotic twins (PDMZTs) offer a unique opportunity to study post-zygotic genetic variation and provide insights into the linkage between genotype and phenotype. We report a comprehensive analysis of a pair of PDMZTs. METHODS: Dysmorphic features and delayed neuro-motor development were observed in the proband, whereas her twin sister was phenotypically normal. Four tissues (blood, skin, hair follicles, and buccal mucosa) from both twins were studied using four complementary methods, including whole-exome sequencing, karyotyping, array CGH, and SNP array. RESULTS: In the proband, tetrasomy 18p affecting all studied tissues except for blood was identified. Karyotyping of fibroblasts revealed isochromosome 18p [i(18p)] in all metaphases. The corresponding analysis of the phenotypically normal sister surprisingly revealed low-level mosaicism (5.4%) for i(18p) in fibroblasts. CONCLUSION: We emphasize that when mosaicism is suspected, multiple tissues should be studied and we highlight the usefulness of non-invasive sampling of hair follicles and buccal mucosa as a convenient source of non-mesoderm-derived DNA, which complements the analysis of mesoderm using blood. Moreover, low-level mosaic tetrasomy 18p is well tolerated and such low-level mosaicism, readily detected by karyotyping, can be missed by other methods. Finally, mosaicism for low-level tetrasomy 18p might be more common in the general population than it is currently recognized, due to detection limitations.

Cytochrome P450 2C19 polymorphism, suboptimal reperfusion and all-cause mortality in patients with acute myocardial infarction.

OBJECTIVES: To determine whether the 681 G>A (*2) polymorphism of cytochrome P450 (CYP2C19) is related to suboptimal reperfusion and mortality in patients with acute myocardial infarction (AMI) pretreated with clopidogrel. METHODS: The study included 276 consecutive patients with AMI in whom percutaneous coronary intervention (PCI) with stenting was attempted. Four-year follow-up for all-cause mortality was obtained. RESULTS: There were 15 failed procedures (5.4%). In the remaining 261 patients, suboptimal reperfusion (post-PCI TIMI flow <3) was observed in 12.6% of the cases. There were 56 carriers (50 heterozygous and 6 homozygous) of CYP2C19*2. The prevalence of carriers in patients with suboptimal flow was 39.4% in comparison to 18.9% in the other patients (p = 0.01). Independent predictors of suboptimal reperfusion were initial TIMI flow ≤1 (OR = 5.9, 95% CI 2.2-16.2, p = 0.001) and CYP2C19*2 (OR = 2.9, 95% CI 1.3-6.6, p = 0.01). Thirty patients died during follow-up (11.5%). Four-year mortality tended to be higher in carriers of CYP2C19*2 (17.9%) versus non-carriers (9.8%; p = 0.09), but the only independent predictors of death were age (HR = 2.0, 95% CI = 1.4-2.8, p = 0.0001) and suboptimal reperfusion (HR = 3.6, 95% CI 1.5-8.8, p = 0.004). CONCLUSIONS: The CYP2C19*2 allele is an independent predictor of suboptimal reperfusion in patients with AMI undergoing PCI with stenting after pretreatment with clopidogrel and may increase the risk of all-cause mortality.

The association between the insertion/deletion polymorphism of the angiotensin-converting enzyme gene and the plasma fibrinogen level in women and men with premature coronary artery atherosclerosis.

INTRODUCTION: The insertion/deletion (I/D) polymorphism of the angiotensin­converting enzyme (ACE) gene is associated with younger age at coronary artery disease (CAD) onset. Some data indicate the relationship between the DD genotype and the fibrinogen level. At the same time, the regulation of the renin-angiotensin system differs in women and men. OBJECTIVES: The objective of the study was to evaluate the sex­dependentassociation of the ACE I/D polymorphism with the plasma fibrinogen level in patients with premature CAD. PATIENTS AND METHODS: The study included 407 participants with premature CAD: 257 women not older than 55 years and 150 men not older than 45 years. Study participants had at least 1 stenosis ≥50% in a major epicardial coronary artery. The ACE I/D polymorphism (rs4343) was genotyped using polymerase chain reaction. Fibrinogen levels were measured with a modified Clauss method. We found a significant interaction indicating that sex modifies the influence of the I/D polymorphism of the ACE gene on fibrinogen levels (P = 0.02). The highest mean fibrinogen level, adjusted for age and smoking status, was observed in women with the DD genotype (575.7 mg/dl) and it was significantly higher than in men with the DD genotype (367.1 mg/dl; P <0.001) or in women with the ID genotype (491.7 mg/dl; P = 0.04). In men, there was no significant difference in mean adjusted fibrinogen levels across genotypes. CONCLUSIONS: The DD genotype of the ACE gene was associated with higher plasma fibrinogen levels in women with premature CAD yet not in men.

Analysis of De Novo Mutations in Sporadic Cardiomyopathies Emphasizes Their Clinical Relevance and Points to Novel Candidate Genes.

The vast majority of cardiomyopathies have an autosomal dominant inheritance; hence, genetic testing is typically offered to patients with a positive family history. A de novo mutation is a new germline mutation not inherited from either parent. The purpose of our study was to search for de novo mutations in patients with cardiomyopathy and no evidence of the disease in the family. Using next-generation sequencing, we analyzed cardiomyopathy genes in 12 probands. In 8 (66.7%), we found de novo variants in known cardiomyopathy genes (TTN, DSP, SCN5A, TNNC1, TPM1, CRYAB, MYH7). In the remaining probands, the analysis was extended to whole exome sequencing in a trio (proband and parents). We found de novo variants in genes that, so far, were not associated with any disease (TRIB3, SLC2A6), a possible disease-causing biallelic genotype (APOBEC gene family), and a de novo mosaic variant without strong evidence of pathogenicity (UNC45A). The high prevalence of de novo mutations emphasizes that genetic screening is also indicated in cases of sporadic cardiomyopathy. Moreover, we have identified novel cardiomyopathy candidate genes that are likely to affect immunological function and/or reaction to stress that could be especially relevant in patients with disease onset associated with infection/infestation.

Angiotensin-converting enzyme polymorphism and completed suicide: an association in Caucasians and evidence for a link with a method of self-injury.

BACKGROUND/AIMS: An association between the II genotype of the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and suicide was found among Japanese men. Our purpose was to replicate this finding in Caucasians and explore other putative genotypic associations among suicides. METHODS: The ACE genotypes were studied by a 2-stage PCR method in 150 completed suicides and 165 age- and sex-matched controls. RESULTS: We found an increase in the frequency of the ACEI allele among male victims of suicide compared to male controls (odds ratio, OR = 1.69, p < 0.006), female suicides (OR = 2.01, p = 0.006) and pooled controls (OR = 1.77, p = 0.001). Analysis of genotype distribution showed that the codominant model had the best fit (p = 0.7) whereas the recessive model could be rejected (p = 0.04). Among males we found an association between the number of the ACE I allele and the method of suicide: OR = 17.98, p(corrected) = 0.00003, for jumping from a height; OR = 0.36, p(corrected) = 0.048, for hanging. We also observed a trend for a negative effect of the number of copies of the ACE I allele on prevalence of depression (OR = 0.36, p = 0.013) and a trend for an effect on age at death (p = 0.021). CONCLUSIONS: Our results suggest that low ACE activity associated with the I allele is a risk factor for suicide, especially in a subset of males. This may be of concern given the widespread use of drugs lowering ACE activity.

Influence of C3435T multidrug resistance gene-1 (MDR-1) polymorphism on platelet reactivity and prognosis in patients with acute coronary syndromes.

BACKGROUND: Genetic C3435T polymorphism of the multidrug resistance gene-1 (MDR-1) limits oral bioavailability of clopidogrel and influences prognosis in patients with myocardial infarction. AIM: To assess the effects of C3435T polymorphism on platelet reactivity and prognosis in patients with acute coronary syndromes treated with percutaneous coronary intervention with stenting. METHODS: Ninety-eight patients were divided into subgroups according to closure time (CT) measured with the Platelet Function Analyzer-100 by means of collagen/adenosine diphosphate (CADP) and collagen/epinephrine (CEPI) cartridges. Patients with CADP-CT<130 s and patients with CEPI-CT

Post-zygotic diploidization of triploidy in human is possible? - a case of triploid partial molar pregnancy resulting in a premature live-born diploid female infant.

OBJECTIVE: During the treatment of our patient we found that reports covering possible complications and their treatment are very scarce. Due to advancement in ultrasound diagnosis most of molar pregnancies are terminated in first trimester of pregnancy. There is the gap in knowledge concerning pregnancy complications in case of partial mole discovered in advanced pregnancy. This is why we incorporated extensive and up-to-date review of literature in our manuscript. METHOD: We described a case of previously healthy, 25 year old primigravida who delivered live daughter at 27 weeks of gestation, complicated with unusual ultrasound appearance of the placenta, severe hypotrophy, and subsequent post-partum eclampsia. RESULTS: Healthy diploid female infant, now two years old and healthy mother taking care of her. CONCLUSIONS: In clinical practice early diagnosis of this complication usually lead to pregnancy termination. In modern medicine, decisions should be based on evidence and patient-doctor mutual understanding. Termination of pregnancy with suspicion of molar placenta can be specially difficult in gestation in older nulliparous women or after ART. We sincerely hope that this report will be useful for physicians across the world in counseling and treating their patients.

Novel calcineurin A (PPP3CA) variant associated with epilepsy, constitutive enzyme activation and downregulation of protein expression.

PPP3CA encodes calmodulin-binding catalytic subunit of calcineurin, a ubiquitously expressed calcium/calmodulin-regulated protein phosphatase. Recently de novo PPP3CA variants were reported as a cause of disease in 12 subjects presenting with epileptic encephalopathy and dysmorphic features. We describe a boy with similar phenotype and severe early onset epileptic encephalopathy in whom a novel de novo c.1324C>T (p.(Gln442Ter)) PPP3CA variant was found by whole exome sequencing. Western blot experiments in patient's cells (EBV transformed lymphocytes and neuronal cells derived through reprogramming) indicate that despite normal mRNA abundance the protein expression level is strongly reduced both for the mutated and wild-type protein. By in vitro studies with recombinant protein expressed in E. coli we show that c.1324C>T (p.(Gln442Ter)) results in constitutive activation of the enzyme. Our results confirm the role of PPP3CA defects in pathogenesis of a distinct neurodevelopmental disorder including severe epilepsy and dysmorphism and provide further functional clues regarding the pathogenic mechanism.

Effect of protein convertase subtilisin/kexin type 9 (PCSK9) 46L gene polymorphism on LDL cholesterol concentration in a Polish adult population.

The purpose was to study the effect of PCSK9 46L on cholesterol concentration and cardiovascular morbidity. By comparing 176 carriers with 6618 non-carriers identified through a cross-sectional population study (WOBASZ) we confirmed the LDL lowering effect of PCSK9 46L and demonstrated that it increases with the concentration of LDL. We noted that PCSK9 46L was associated with tendency for protection from myocardial infarction but not stroke suggesting a difference in the effect on susceptibility to these disorders.

Polymorphism of the oestrogen receptor beta gene (ESR2) is associated with susceptibility to Graves' disease.

OBJECTIVE: To investigate whether a polymorphism in the ESR2 gene (rs4986938, previously associated with endometriosis, ovulatory dysfunction and premature onset of coronary heart disease) increases the risk of Graves' disease (GD). SUBJECTS AND DESIGN: A cohort of 375 GD patients (300 females and 75 males) and 1001 individuals representative of the background population of Poland (502 males and 499 females) were genotyped for rs4986938 using allele-specific polymerase chain reaction (PCR). RESULTS: We found an increased frequency of the ESR2 A allele among the patients vs. controls (38.0%vs. 32.7%, OR = 1.26, P = 0.009) that was caused by a co-dominant (OR = 1.25, P = 0.01, P(for model fit) = 0.127) or a recessive (OR = 1.67, P = 0.003, P(for model fit) = 0.554) effect. The association was found in both sexes (OR = 1.21, P = 0.046 and OR = 1.53, P = 0.029, respectively, for co-dominant and recessive models in females, and OR = 1.44, P = 0.034 and OR = 2.29, P = 0.01, respectively, for the two models in males) and was more pronounced among the DRB1*03-negative (OR = 1.63, P = 0.0002) than DRB1*03-positive patients (OR = 1.04, P = 0.822). No other statistically significant associations between the ESR2 genotype and GD subsets were found (age of onset, smoking, clinically evident ophthalmopathy, family history of GD, and PTPN22 and CTLA4 (CT60) genotypes were analysed). CONCLUSIONS: In a Polish population the ESR2 A allele is associated with GD with a strength comparable to polymorphisms of PTPN22 and CTLA4 CT60 loci (OR approximately 1.7). The association with ESR2 is found in both sexes and may be particularly strong among the DRB1*03-negative individuals.